Ho fatto così:
codice:
Dim sr As StreamReader
Dim nomefile As String = ListBox1.SelectedItem.ToString

Try
sr = New StreamReader("DATA\ProgS\" & nomefile & ".ini") 
programma.Text = sr.ReadToEnd() 
Catch 
Finally 
End Try 
If My.Computer.FileSystem.FileExists(programma.Text) = True Then
            Shell(programma.Text)
        Else
            MsgBox("Il programma non esiste!")
        End If